Induction of hypoxia-inducible factor-1alpha in two kinds of rats asphyxiation death models

OBJECTIVE: To investigate the expression of hypoxia-inducible factor 1-alpha (HIF1-alpha) in the heart, lung, liver and kidney in rats died of two typical models of asphyxia. METHODS: Two asphyxia models were made and tissue samples of the dead rats were collected from different groups at various postmortem duration. The expression and the changes of HIF1-alpha in various tissues were examined by immunohistochemistry and image analysis techniques. Results Significant expression of HIF1-alpha was observed in the myocardial fibers, kidney cells, liver cells and lung cells in both asphyxia models, but not in the control group. The expression of HIF1-alpha in various tissues in the rat died of nitrogen gas breathing was found in the nuclei at 0 hour and the expression level decreased gradually thereafter. The HIF1-alpha expression level and duration in various tissues of the rat died of hanging were higher and longer than that of the former group, with a peak of the expression level observed 6 hours after death, and then started to decline in all tissues except the heart where the expression still showed an increase 24 hours after death. The control groups showed a steady expression in the cytoplasm but not in the nuclei. CONCLUSION: HIF1-alpha appears to be a valuable biomarker in the diagnosis of asphyxia within 24 hours after death.